Modeling shallow water propagation with scattering from rough boundaries

Results of PE simulations at 3 kHz will be described for propagation in a shallow water waveguide with a rough sea surface and a flat water-sediment interface overlying absorbing sediments. Pressure fields are simulated in two space dimensions and have been obtained using a wide-angle PE code that accounts for scattering from a rough sea surface. The PE simulation approach is a Monte Carlo method, requiring solutions for many surface realizations in order to obtain results for field moments. To obtain a fast, yet accurate model for average field quantities, a transport theory method based on coupled modes has been developed for both the first and second moments of the field. Estimates for the fourth moment of the field have also been obtained based on the transport theory results for the first and second moments. Transport theory results for the coherent and total intensity, and for the scintillation index, will be presented and compared with Monte Carlo simulations.